Device for placing a marker into a human subject for the purpose of tissue biopsy

Abstract

The present invention is a marker delivery device designed to deliver an elongated magnet to mark the center of tissue that is suspected of being cancerous. This device has an elongated magnet situated within a hollow needle with the magnet's distal end placed at the distal end of the needle. The operator first places the tip of the needle at the center of the lesion. By pressing an activate button on the injector device, the needle is advanced by half the length of the magnet and then pulled back the full length of the magnet while a rod within the needle that is in contact with the proximal end of the magnet prevents the magnet from coming back when the needle goes back. Thus the magnet is deployed with its center at the center of the lesion that is suspected of being cancerous.

1 . A marker delivery device having an elongated permanent magnet of length “2L” placed within a distal section of an elongated hollow needle that is situated at a distal section of the marker delivery device, the marker delivery device having a cylindrical push rod placed within the needle such that the distal end of the rod is in contact with the proximal end of the magnet and the distal end of the magnet is generally situated at the distal end of the needle, the distal tip of the needle being adapted to be placed at a first position which is at the approximate center of tissue within a human subject that is suspected of being cancerous, the marker delivery device then being actuated to advance the needle tip to a second position which advances the distal end of the needle, and the distal end of the rod and also advances the position of the magnet by an approximate distance “L”, the marker delivery device then retracting the needle in a backward direction by the approximate distance “2L” to a third position while the rod and magnet remain fixed in their second position so that the magnet is released from the needle with the center of the magnet being placed at the approximate center of the tissue that is thought to be cancerous. 
     
     
         2 . The marker delivery device of  claim 1  where the magnet has a center anchor that exerts a frictional force on the interior of the needle prior to release of the magnet into the human tissue and the center anchor opens outwardly after it is ejected from the needle so as to maintain the magnet at the approximate center of the tissue that is suspected of being cancerous. 
     
     
         3 . The marker delivery device of  claim 1  where the magnet is formed from a permanent magnetic material such as Arnochrome 3, Vicalloy, Alnico 5 or a rare Earth metal. 
     
     
         4 . A needle assembly consisting of a needle with a sharpened tip and an elongated permanent magnet placed within a distal portion of that needle, the needle also having a Luer fitting fixedly attached at its proximal end which is removably attached to a Luer fitting that is fixedly attached to the proximal end of an elongated rod situated within the needle with the distal end of the rod being in contact with the proximal end of the elongated permanent magnet, the needle assembly plus elongated rod being adapted for the needle tip to be placed at a first position which is at the approximate center of tissue within a human subject that is suspected of being cancerous. 
     
     
         5 . The needle assembly of  claim 4  being attached to a MagneJector that is capable of a forward motion of one half the length of the magnet followed by a backward motion of at least the length of the magnet so as to release the magnet into the female breast with the center of the magnet being at the approximate center of the tissue that is to be excised by a surgeon.